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Sub-Saharan Africa had between 1.4 and 2.4 million new HIV infections in the last year, according to the most recent UNAIDS report—back in 2001, new infections were higher, between 1.7 and 2.7 million. HIV prevalence in adults is estimated at 5% in sub-Saharan Africa, down from its almost-6% estimate in 2000. That's one reason why there's something really, really odd about the conclusion of Michael Specter's fascinating piece on viruses in the New Yorker.

[U of C Irvine's Center for Virus Research director Luis P.] Villarreal predicts that, without an effective AIDS vaccine, nearly the entire population of Africa will eventually perish. "We can also expect at least a few humans to survive,'' he wrote. They would be people who have been infected with H.I.V. yet, for some reason, do not get sick. "These survivors would thus be left to repopulate the continent. However, the resulting human population would be distinct" from those whom H.I.V. makes sick.

The entire population??? Well, "eventually" can be a very long time, as it would be in the context of evolution. But that "eventually" in that case is tied to a lack of an AIDS vaccine. And while there are 2 million AIDS deaths or so a year in Africa, there are more than 10 times as many births. Even though population growth rate is projected to slow radically, Africa does have nearly a population of one billion people. (Well, 920 million or some such?) I spent 5 minutes with a calculator and didn't get very far—is there anyone more math-friendly who can "eventually" get a "zero" population figure on Africa?